What should I be prepared for, in filing my taxes when I have to file in 2 different states, having sold a home in FL and purchasing a home in Ga, and also retiring?

You will be filing a part-year GA return.  FL has no state income tax so unless you have something you have not mentioned like rental property or a FL based business, you will not file a FL return.

https://ttlc.intuit.com/questions/1901227-how-do-i-file-a-part-year-state-return

As for selling your home:

If your gain was more than  $250,000 filing Single, or more than $500,000 filing Married Filing Jointly the sale must be reported on your tax return.  Whether you re-invested the gain in to another house is irrelevant.  If you  have a Form 1099-S go to Federal>Wages and Income>Less Common Income>Sale of Home (gain or loss)

If you owned and lived in the home as your primary residence for at least 2 of the last 5 years on the date of the sale, you do not have to report the home sale if the gain is less than $250K filing Single, or less than $500K filing Married Filing Jointly (and you both owned and lived in the home for at least 2 years).

• If you are using online TT, you need Premium software to report the 1099-S

If you have retired and are receiving retirement income like Social Security, pension or retirement account distributions, those are entered in a different place in the software.

Social Security sends you a SSA1099 in January

Do not try to enter your SSA1099  or RR1099RB as a W-2.  Go to Federal> Wages & Income>>Retirement Plans and Social Security  (SSA1099 and 1099RRB) to enter your SSA1099.

Pensions and/or many other kinds of retirement income are reported on a  1099R that you will get in late January or early February

To enter your retirement income, Go to  Federal> Wages and Income>Retirement Plans and Social Security>IRA  401 k) Pension Plan Withdrawals to enter your 1099R.